Research on Highly Sensitive Quantitative Nondestructive Evaluation Techniques of Closed Cracks and Branched Cracks

闭合裂纹和分支裂纹高灵敏定量无损评价技术研究

基本信息

批准号：
16360048
负责人：
SAKA Masumi
金额：
$ 9.15万
依托单位：
Tohoku University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16360048/
关键词：
Nuclear Power Plant Non-Destructive Testing Closed Cracks Branched Cracks Welded Part Ultrasonic Testing Nonlinear Ultrasonics Direct Current Potential Drop Technique 原子力エネルギー逆問題解析裏面き裂

项目摘要

1. Enhancement of signal-to-noise ratio by optimizing the averaging conditions for reducing the ultrasonic scattering noiseAustenitic stainless steel, AISI316L, was treated in this study. For reducing the ultrasonic scattering noise from the grain boundary, the optimum sampling conditions and the optimum scanning conditions were obtained.2. Ultrasonic inspection of closed back-wall cracks in welded partSpecimens containing the unknown fatigue cracks were prepared, and the crack closure stress and the depth of cracks have been successfully determined by solving the ultrasonic inverse problem. Furthermore, it was shown that the ultrasonic responses for stress corrosion cracking at the back-wall of the thick-walled welded specimen were enhanced remarkably by cooling the surface of the specimen with Dry Ice and ethanol.3. Evaluation of closed cracks by nonlinear ultrasonicsThe nonlinear ultrasonic technique was adopted to inspect the closed cracks, and the relationships between the behavio … More r of nonlinear ultrasonic waves and the crack closure stress were obtained. Furthermore, by using the second harmonic waves, weak bonding, stress corrosion cracking, and so on were visualized.4. Enhancement of sensitivity of DCPD techniqueThe sensitive direct current potential drop technique, which controls the current flow in the tested pipe by locally heating the outer surface of the pipe, has been proposed, and the ability of the present technique has been provided. Furthermore, a new DCPD sensor with repeatable contact unit for the probes has been developed, and the precise and repeatable measurements of potential drop have been achieved.5. Combination of various techniques for reliable QNDEAbilities of ultrasonic inspection including that of nonlinear ultrasound and sensitive DCPD techniques were compared for inspecting the various types of specimens having flaws. It was verified that the combination of these techniques were effective for realizing the reliable QNDE of closed cracks and branched cracks. Less

1。通过优化减少超声散射Noiseaustenitic不锈钢AISI316L的平均条件的平均条件来提高信噪比。为了减少从晶界的超声散射噪声，获得最佳采样条件和最佳扫描条件。2。制备了包含未知疲劳裂纹的焊接部分的封闭后壁裂纹的超声检查，并通过解决超声逆问题成功确定了裂纹闭合应力和裂纹的深度。此外，表明，通过用干冰和乙醇冷却样品表面3。通过非线性超声检查对闭合裂纹的评估，采用了非线性超声技术来检查闭合裂纹，并获得了行为……更多的非线性超声波和裂纹闭合应力。此外，通过使用第二个谐波波，弱粘结，应力腐蚀开裂等，可视化。4。已经提出了通过局部加热管道的外表面来控制测试管中的电流流动的敏感性敏感性的灵敏度，并提供了当前技术的能力。此外，已经开发了具有可重复接触单元的新的DCPD传感器，并且已经达到了对潜在降低的精确测量值。5。比较了各种技术的超声检查QNDEABISS，包括非线性超声和灵敏的DCPD技术的组合，以检查具有缺陷的各种样本。据证实，这些技术的组合有效地实现了可靠的封闭裂纹和分支裂纹的QNDE。较少的